Composite filler

ABSTRACT

A method and apparatus is presented. Layers of composite material are laid down on a forming tool. A respective bend is formed in each of the layers to form the composite filler comprising bent layers on the forming tool. The composite filler comprising the bent layers is placed into a gap formed by at least one composite structure.

BACKGROUND INFORMATION

1. Field

The present disclosure generally relates to composite structures and, inparticular, to the fabrication of composite structures. Still moreparticularly, the present disclosure relates to a method and apparatusfor producing composite fillers used to fill gaps in compositestructures.

2. Background

Composite materials are tough, lightweight materials created bycombining two or more functional components. For example, a compositematerial may include reinforcing fibers bound in polymer resin matrix.The fibers may be unidirectional or may take the form of a woven clothor fabric. In thermoset composites, fibers and resins are arranged andcured to form a composite material.

When composite structural members are joined together, gaps or voids maybe present along bond lines between the members which may need to befilled in order to increase the strength of the bond. For example, inthe aircraft industry, composite fuselage stiffeners such as stringersmay include adhesive filler at the radius bond line between the stringerand a fuselage skin. The adhesive filler is applied in the form oftriangular cross section strips, sometimes referred to as noodles orfillers, which fill the voids at the bond line. The adhesive filler maybe formed from composite materials such as adhesive, prepreg tape orfabric.

When a stiffener possesses sufficient pull-off strength in the area ofthe filler, the stiffener resists tension loads imposed on the stiffenerfor a given application. In order to achieve adequate pull-off strength,it may be necessary to increase the gauge of the stiffener, therebyadding weight to the aircraft. Alternatively, radius blocks may be addedto the stiffeners in order to increase pull-off strength, but the radiusblocks may add undesirable weight, complexity, or cost to the aircraft.

The filler may be formed by extruded material, rolled compositematerial, or stacked strips of composite material parallel to theaircraft skin. When the filler is of sufficient stiffness, the fillermay transfer some of the load from the stiffener into the base. If thefiller is not sufficiently strong it may not function to transfer load.

Therefore, it would be desirable to have a method and apparatus thattake into account at least some of the issues discussed above, as wellas other possible issues.

SUMMARY

An illustrative embodiment of the present disclosure provides a methodof forming a composite filler. Layers of composite material are laiddown on a forming tool. A respective bend is formed in each of thelayers to form the composite filler comprising bent layers on theforming tool. The composite filler comprising the bent layers is placedinto a gap formed by at least one composite structure.

Another illustrative embodiment of the present disclosure provides acomposite filler. The composite filler comprises a first layer having afirst bent shape and a second layer having a second bent shape.

Yet another illustrative embodiment of the present disclosure provides acomposite filler. The composite filler comprises a plurality ofcomposite layers, each composite layer having a respective bent shape.

The features and functions can be achieved independently in variousembodiments of the present disclosure or may be combined in yet otherembodiments in which further details can be seen with reference to thefollowing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the illustrativeembodiments are set forth in the appended claims. The illustrativeembodiments, however, as well as a preferred mode of use, furtherobjectives and features thereof, will best be understood by reference tothe following detailed description of an illustrative embodiment of thepresent disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an illustration of an aircraft in which an illustrativeembodiment may be implemented;

FIG. 2 is an illustration of an isometric view of a composite filler anda composite structural member in accordance with an illustrativeembodiment;

FIG. 3 is an illustration of a front view of a composite filler and acomposite structural member in accordance with an illustrativeembodiment;

FIG. 4 is an illustration of a front view of a composite filler inaccordance with an illustrative embodiment;

FIG. 5 is an illustration of a first layer and shaping equipment inaccordance with an illustrative embodiment;

FIG. 6 is an illustration of a first layer having a first bent shape andshaping equipment in accordance with an illustrative embodiment;

FIG. 7 is an illustration of a second layer, a first layer having afirst bent shape, and shaping equipment in accordance with anillustrative embodiment;

FIG. 8 is an illustration of a first layer having a first bent shape, asecond layer having a second bent shape, and shaping equipment inaccordance with an illustrative embodiment;

FIG. 9 is an illustration of a plurality of layers having respectivebent shapes and shaping equipment in accordance with an illustrativeembodiment;

FIG. 10 is an illustration of a first die punch in accordance with anillustrative embodiment;

FIG. 11 is an illustration of a second die punch in accordance with anillustrative embodiment;

FIG. 12 is an illustration of a third die punch in accordance with anillustrative embodiment;

FIG. 13 is an illustration of a fourth die punch in accordance with anillustrative embodiment;

FIG. 14 is an illustration of a fifth die punch in accordance with anillustrative embodiment;

FIG. 15 is an illustration of a sixth die punch in accordance with anillustrative embodiment;

FIG. 16 is an illustration of a flowchart of a process for forming acomposite filler in accordance with an illustrative embodiment;

FIG. 17 is an illustration of a block diagram of a manufacturingenvironment in accordance with an illustrative embodiment;

FIG. 18 is an illustration of a block diagram of an aircraftmanufacturing and service method in accordance with an illustrativeembodiment; and

FIG. 19 is an illustration of a block diagram of an aircraft in which anillustrative embodiment may be implemented.

DETAILED DESCRIPTION

The illustrative embodiments recognize and take into account one or moredifferent considerations. The illustrative embodiments recognize andtake into account that plies following a radius may direct a load alongthe radius. Accordingly, the illustrative embodiments recognize and takeinto account that forming a filler of plies following a radius of astiffener may direct a load along the radius rather than into thefiller. Thus, the illustrative embodiments recognize and take intoaccount that forming a filler following a radius of a stiffener mayincrease the pull-off strength of the filler.

The illustrative examples further recognize and take into account thatforming a filler following a radius of a stiffener may have additionaladvantages. Specifically, the illustrative examples take into accountthat a filler may have advantageous thermal behavior at least one ofduring or following the cure cycle when the filler material is comprisedof a similar shape and form of the material of the composite structuralmembers.

With reference now to the figures, and in particular, with reference toFIG. 1, an illustration of an aircraft is depicted in which anillustrative embodiment may be implemented. In this illustrativeexample, aircraft 100 has wing 102 and wing 104 attached to body 106.Aircraft 100 includes engine 108 attached to wing 102 and engine 110attached to wing 104.

Body 106 has tail section 112. Horizontal stabilizer 114, horizontalstabilizer 116, and vertical stabilizer 118 are attached to tail section112 of body 106.

Aircraft 100 is an example of an aircraft in which a composite fillermay be implemented in accordance with an illustrative embodiment. Forexample, composite fillers may be placed between stiffeners 120 andcomposite skin 122 of aircraft 100. FIG. 1 depicts an exposed view ofstiffeners 120.

This illustration of aircraft 100 is provided for purposes ofillustrating one environment in which the different illustrativeembodiments may be implemented. The illustration of aircraft 100 in FIG.1 is not meant to imply architectural limitations as to the manner inwhich different illustrative embodiments may be implemented. Forexample, aircraft 100 is shown as a commercial passenger aircraft. Thedifferent illustrative embodiments may be applied to other types ofaircraft, such as private passenger aircraft, a rotorcraft, and othersuitable type of aircraft.

Turning now to FIG. 2, an illustration of an isometric view of acomposite filler and a composite structural member is depicted inaccordance with an illustrative embodiment. Specifically, FIG. 2 is anenlarged view of stiffener 202 of stiffeners 120 in section 2-2 ofFIG. 1. As depicted, composite filler 204 is placed in gap 206 formed bystiffener 202 and composite skin 122. In this illustrative example,composite filler 204 has a substantially triangular cross-section.Although stiffener 202 is a single composite structural member, in someillustrative examples, stiffener 202 may instead be two or morecomposite structural members. Throughout, “composite structural member”and “composite structure” may be used interchangeably. In someillustrative examples, stiffener 202 is a composite stringer.

Turning now to FIG. 3, an illustration of a front view of a compositefiller and a composite structural member is depicted in accordance withan illustrative embodiment. Specifically, FIG. 3 is a view of stiffener202, composite filler 204, and composite skin 122 from direction 3-3 ofFIG. 2.

Stiffener 202 has radius 300 and radius 302. First side 304 of compositefiller 204 follows radius 300. Second side 306 of composite filler 204follows radius 302.

Turning now to FIG. 4, an illustration of a front view of a compositefiller is depicted in accordance with an illustrative embodiment.Composite filler 400 may be an embodiment of composite filler 204 inFIG. 2 and FIG. 3. Composite filler 400 is formed of plurality of layers402. Plurality of layers 402 are formed of at least one compositematerial.

Plurality of layers 402 may comprise one or more ply orientations.Specifically, plurality of layers 402 may have at least one of 0 degreeplies, +/−10 degree plies, +/−15 degree plies, +/−30 degree plies, +/−45degree plies, +/−60 degree plies, +/−75 degree plies, or +/−90 degreeplies.

As used herein, the phrase “at least one of,” when used with a list ofitems, means different combinations of one or more of the listed itemsmay be used and only one of each item in the list may be needed. Inother words, “at least one of” means any combination of items and numberof items may be used from the list but not all of the items in the listare required. The item may be a particular object, thing, or a category.

For example, “at least one of item A, item B, or item C” may include,without limitation, item A, item A and item B, or item B. This examplealso may include item A, item B, and item C or item B and item C. Ofcourse, any combinations of these items may be present. In otherexamples, “at least one of” may be, for example, without limitation, twoof item A; one of item B; and ten of item C; four of item B and seven ofitem C; or other suitable combinations.

In this illustrative example, plurality of layers 402 includes firstlayer 404, second layer 406, third layer 408, fourth layer 410, fifthlayer 412, sixth layer 414, seventh layer 416, eighth layer 418, ninthlayer 420, tenth layer 422, eleventh layer 424, and twelfth layer 426.Although plurality of layers 402 includes twelve layers in thisillustrative example, plurality of layers 402 may include any number oflayers equal to or greater than two layers.

Each of plurality of layers 402 has respective bent shapes 428. Each ofrespective bent shapes 428 may have a different angle. Each of pluralityof layers 402 may stack or nest to form composite filler 400.

As can be seen from FIG. 4, each layer of plurality of layers 402 has arespective length. In this illustrative example, first layer 404 islonger than each other layer in plurality of layers 402. In thisillustrative example, each successive layer in plurality of layers 402is shorter than each previous layer. For example, third layer 408 isshorter than both second layer 406 and first layer 404.

First layer 404 forms first side 430 and second side 432 of compositefiller 400. First side 430 and second side 432 of composite filler 400may contact a composite structural member. First side 430 has radius433. Second side 432 has radius 435. Plurality of layers 402 followsradius 433 and radius 435. Plurality of layers 402 following radius 433and radius 435 may direct a load along at least one of radius 433 andradius 435. Third side 434 of composite filler 400 is formed ofplurality of layers 402. Third side 434 may contact a composite partsuch as a composite skin.

As depicted, composite filler 400 includes extruded material 436.Extruded material 436 is positioned next to twelfth layer 426. Extrudedmaterial 436 may be present to fill a gap in composite filler 400. Insome examples, composite filler 400 may only have plurality of layers402.

As depicted, each of plurality of layers 402 comprises a single ply.However, in other illustrative examples, at least one of plurality oflayers 402 may comprise multiple plies.

Turning now to FIG. 5, an illustration of a first layer and shapingequipment is depicted in accordance with an illustrative embodiment.Manufacturing environment 500 may be an example of a manufacturingenvironment for forming composite filler 400 in FIG. 4. Manufacturingenvironment 500 includes shaping equipment 502 and first layer 504.First layer 504 may be formed of a composite material. In illustrativeexamples in which first layer 504 is formed of a composite material,first layer 504 may also be referred to as a first composite layer.First layer 504 has length 505. Shaping equipment 502 includes first diepunch 506 and base 508.

As depicted, base 508 includes first portion 510, second portion 512,and gap 514. To form a composite filler, first die punch 506 may bemoved towards base 508 in the direction of arrow 516. By moving firstdie punch 506 towards base 508, shaping equipment 502 may change theshape of first layer 504. In this example, first die punch 506 contactsfirst layer 504 and applies a load on first layer 504 in the directionof arrow 516. Specifically, by moving first die punch 506 towards base508, shaping equipment 502 may form first layer 504 to base 508.

Turning now to FIG. 6, an illustration of a first layer having a firstbent shape and shaping equipment is depicted in accordance with anillustrative embodiment. As depicted, first layer 504 has been formed tobase 508. The movement of first die punch 506 towards base 508 in thedirection of arrow 516 in FIG. 5 has changed the shape of first layer504. As depicted, first layer 504 has first bent shape 602. First layer504 contacts first portion 510 and second portion 512 and extends intogap 514.

Turning now to FIG. 7, an illustration of a second layer, a first layerhaving a first bent shape, and shaping equipment is depicted inaccordance with an illustrative embodiment. As depicted, manufacturingenvironment 500 includes shaping equipment 502, first layer 504, andsecond layer 702. In this example, shaping equipment 502 includes base508 and second die punch 704. As depicted first layer 504 is formed tobase 508, and second layer 702 having length 706 is positioned relativeto first layer 504.

Second layer 702 may be formed of a composite material. In illustrativeexamples in which second layer 702 is formed of a composite material,second layer 702 may also be referred to as a second composite layer.Length 706 of second layer 702 is less than length 505 of first layer504 in FIG. 5. Further, shape of second die punch 704 is different thanthe shape of first die punch 506 in FIG. 5.

To form the composite filler, second die punch 704 may be moved towardsbase 508 in the direction of arrow 516. In this example, second diepunch 704 contacts second layer 702 and applies a load on second layer702 in the direction of arrow 516. By moving second die punch 704towards base 508, shaping equipment 502 may change the shape of secondlayer 702. Specifically, by moving second die punch 704 towards base508, shaping equipment 502 may form second layer 702 to first layer 504.

Turning now to FIG. 8, an illustration of a first layer having a firstbent shape, a second layer having a second bent shape, and shapingequipment is depicted in accordance with an illustrative embodiment. Asdepicted, second layer 702 has been formed to first layer 504 on base508. Second layer 702 has second bent shape 802. As can be seen fromFIG. 8, second bent shape 802 is different than first bent shape 602such that second layer 702 is formed to first layer 504.

Turning now to FIG. 9, an illustration of a plurality of layers havingrespective bent shapes and shaping equipment is depicted in accordancewith an illustrative embodiment. As depicted, composite filler 900 isformed to base 508. Composite filler 900 is formed from plurality oflayers 901. Plurality of layers 901 comprises first layer 504, secondlayer 702, third layer 902, fourth layer 904, fifth layer 906, sixthlayer 908, seventh layer 910, eighth layer 912, ninth layer 914, tenthlayer 916, eleventh layer 918, and twelfth layer 920. Each of pluralityof layers 901 comprises respective bent shapes 922. Respective bentshapes 922 comprise first bent shape 602 and second bent shape 802 fromFIG. 6 and FIG. 8, respectively.

Each of plurality of layers 901 may be formed into respective bentshapes 922 by a plurality of successive die punches having differentshapes. In some illustrative examples, each die punch of the pluralityof die punches may have a different respective bent shape to form eachsuccessive layer of plurality of layers 901. In other illustrativeexamples, a die punch of the plurality of die punches may be used toform more than one layer of plurality of layers 901. In one illustrativeexample, a die punch of the plurality of die punches may be used to formtwo successive layers of plurality of layers 901.

FIGS. 10-15 are illustrations of die punches that may be used to shape aplurality of layers into bent shapes. Turning first to FIG. 10, anillustration of a first die punch is depicted in accordance with anillustrative embodiment. First die punch 1000 may be an example of firstdie punch 506 from FIG. 5. First die punch 1000 may be used to form acomposite layer such as first layer 504 of FIG. 5.

First die punch 1000 has shaping portion 1001 and base 1003. Shapingportion 1001 has height 1002, cross-section 1004, and angle 1006.

Turning now to FIG. 11, an illustration of a second die punch isdepicted in accordance with an illustrative embodiment. Second die punch1100 may be an example of second die punch 704 from FIG. 7. Second diepunch 1100 may be used to form a composite layer such as second layer702 of FIG. 7.

Second die punch 1100 has shaping portion 1101 and base 1103. Shapingportion 1101 has height 1102, cross-section 1104, and angle 1106. As canbe seen from FIG. 10 and FIG. 11, height 1102 is less than height 1002of first die punch 1000.

Turning now to FIG. 12, an illustration of a third die punch is depictedin accordance with an illustrative embodiment. Third die punch 1200 maybe an example of a successive die punch used on a successive compositelayer after a composite layer is formed using second die punch 1100.Third die punch 1200 may be used to form a composite layer such as thirdlayer 902 of FIG. 9.

Third die punch 1200 has shaping portion 1201 and base 1203. Shapingportion 1201 has height 1202, cross-section 1204, and angle 1206. As canbe seen from FIGS. 10-12, height 1202 is less than both height 1102 andheight 1002 of second die punch 1100 and first die punch 1000,respectively.

Turning now to FIG. 13, an illustration of a fourth die punch isdepicted in accordance with an illustrative embodiment. Fourth die punch1300 may be an example of a successive die punch used on a successivecomposite layer after a composite layer is formed using third die punch1200 in FIG. 12. Fourth die punch 1300 may be used to form a compositelayer such as fourth layer 904 of FIG. 9.

Fourth die punch 1300 has shaping portion 1301 and base 1303. Shapingportion 1301 has height 1302, cross-section 1304, and angle 1306. As canbe seen from FIGS. 10-13, height 1302 is less than height 1202, height1102, and height 1002 of third die punch 1200, second die punch 1100,and first die punch 1000, respectively.

Turning now to FIG. 14, an illustration of a fifth die punch is depictedin accordance with an illustrative embodiment. Fifth die punch 1400 maybe an example of a successive die punch used on a successive compositelayer after a composite layer is formed using fourth die punch 1300 inFIG. 13. Fifth die punch 1400 may be used to form a composite layer suchas fifth layer 906 of FIG. 9.

Fifth die punch 1400 has shaping portion 1401 and base 1403. Shapingportion 1401 has height 1402, cross-section 1404, and angle 1406. As canbe seen from FIGS. 10-14, height 1402 is less than height 1302, height1202, height 1102, and height 1002 of fourth die punch 1300, third diepunch 1200, second die punch 1100, and first die punch 1000,respectively.

Turning now to FIG. 15, an illustration of a sixth die punch is depictedin accordance with an illustrative embodiment. Sixth die punch 1500 maybe an example of a successive die punch used on a successive compositelayer after a composite layer is formed using fifth die punch 1400 inFIG. 14. Sixth die punch 1500 may be used to form a composite layer suchas sixth layer 908 of FIG. 9.

Sixth die punch 1500 has shaping portion 1501 and base 1503. Shapingportion 1501 has height 1502, cross-section 1504, and angle 1506. As canbe seen from FIGS. 10-15, height 1502 is less than height 1402, height1302, height 1202, height 1102, and height 1002 of fifth die punch 1400,fourth die punch 1300, third die punch 1200, second die punch 1100, andfirst die punch 1000, respectively.

The illustrations of the die punches and shaping equipment in FIGS. 5-15are not meant to imply physical or architectural limitations to themanner in which an illustrative embodiment may be implemented. The diepunches in FIGS. 10-15 provide some non-limiting examples of shapes fordie punches. Further, although base 508 as depicted includes firstportion 510, second portion 512, and gap 514, in some illustrativeexamples, shaping equipment 502 may comprise different configurationsthan those depicted. Base 508 is only one non-limiting example of abase, such as base 1758 of FIG. 17 below.

Turning now to FIG. 16, an illustration of a flowchart of a process forforming a composite filler in accordance with an illustrativeembodiment. The process illustrated in FIG. 16 may be implemented in amanufacturing environment such as manufacturing environment 500 of FIG.5 to form a composite filler such as composite filler 400 of FIG. 4. Forexample, the operations of this process may be implemented using shapingequipment 502 of FIG. 5.

The process may begin by laying down layers of composite material on aforming tool (operation 1602). In some illustrative examples, at leastone layer of the layers of the composite material comprises multipleplies of composite material. In some illustrative examples, eachsuccessive layer of composite material has a shorter width than a widthof a previous layer of composite material. For example, in FIG. 4, eachof plurality of layers 402 has successively shorter widths.

The process may then form a respective bend in each of the layers toform the composite filler comprising bent layers on the forming tool(operation 1604). In some illustrative examples, each layer of thelayers of the composite material is laid down and then formed prior tolaying down a successive layer in the layers of the composite material.Illustrative examples of forming successive layers may be seen in FIGS.5-8. In some illustrative examples, forming the respective bend in eachof the layers comprises individually forming a respective bend in eachof the layers.

In some illustrative examples, forming the respective bend in each ofthe layers comprises using a series of die punches, each having arespective cross-section and a desired angle to form a respective bendin one of the layers. FIGS. 10-15 may be examples of die punches eachhaving a respective cross-section and a desired angle. In someillustrative examples, forming the respective bend in each of the layersforms a first side and a second side of the composite filler. As can beseen from FIG. 4, first layer 404 of plurality of layers 402 may formfirst side 430 and second side 432 of composite filler 400.

The process may then add an extruded composite material to the compositefiller (operation 1606). This extruded composite material may optionallybe added to the composite filler before using the composite filler.

The process may then place the composite filler comprising the bentlayers into a gap formed by at least one composite structure (operation1608), with the process terminating thereafter. In some illustrativeexamples, the cross-section of the composite filler is substantiallytriangular. For example, the cross-section of composite filler 400 issubstantially triangular. In some illustrative examples, the at leastone composite structure comprises a composite stringer.

The flowcharts and block diagrams in the different depicted embodimentsillustrate the architecture, functionality, and operation of somepossible implementations of apparatuses and methods in an illustrativeembodiment. In this regard, each block in the flowcharts or blockdiagrams may represent a module, a segment, a function, and/or a portionof an operation or step.

In some alternative implementations of an illustrative embodiment, thefunction or functions noted in the blocks may occur out of the ordernoted in the figures. For example, in some cases, two blocks shown insuccession may be executed substantially concurrently, or the blocks maysometimes be performed in the reverse order, depending upon thefunctionality involved. Also, other blocks may be added in addition tothe illustrated blocks in a flowchart or block diagram. Further, someblocks may not be implemented. For example, operation 1606 may not beperformed. In this example, the composite filler does not includeoptional extruded material.

Turning now to FIG. 17, an illustration of a block diagram of amanufacturing environment is depicted in accordance with an illustrativeembodiment. Manufacturing environment 500 in FIG. 5 is an example of aphysical implementation of manufacturing environment 1700 shown in blockform in FIG. 17.

Manufacturing environment 1700 comprises composite filler 1702, shapingequipment 1704, composite material 1706, and cutting machine 1708.Composite filler 1702 may be configured to be placed in gap 1710 formedby composite structure 1712, composite structure 1714, and compositeskin 1716.

Composite filler 1702 is formed of plurality of layers 1718. Pluralityof layers 1718 may be formed of composite material 1706. In illustrativeexamples in which plurality of layers 1718 is formed of compositematerial 1706, plurality of layers 1718 may also be referred to as aplurality of composite layers. Plurality of layers 1718 has respectivebent shapes 1720. Plurality of layers 1718 has plurality of widths 1722.Specifically, each successive layer may have a smaller width than eachprevious layer in plurality of layers 1718.

First layer 1724 has first width 1726 and first bent shape 1728. Firstwidth 1726 may be the widest of plurality of layers 1718. First bentshape 1728 may have the most acute angle of respective bent shapes 1720of plurality of layers 1718.

Second layer 1730 may be formed on first layer 1724. Second layer 1730has second width 1732 and second bent shape 1734. Second width 1732 maybe smaller than first width 1726 of first layer 1724. Second width 1732may be wider than the remaining of plurality of layers 1718. Second bentshape 1734 may have a wider angle than first bent shape 1728.

Third layer 1736 may be formed on second layer 1730. Third layer 1736has third width 1738 and third bent shape 1740. Third width 1738 may besmaller than first width 1726 and second width 1732. Third bent shape1740 may have a wider angle than second bent shape 1734.

Composite filler 1702 has cross-section 1742. Cross-section 1742 may beconfigured to fit within cross-section 1743 of gap 1710. In someillustrative examples, cross-section 1742 may be substantiallytriangular 1744. Substantially triangular 1744 cross-section 1742 hasfirst side 1746 and second side 1748. First side 1746 of compositefiller 1702 may contact composite structure 1712. In some illustrativeexamples, composite structure 1712 may have radius 1750. In theseillustrative examples, first side 1746 of composite filler 1702 mayfollow radius 1750.

Second side 1748 of composite filler 1702 may contact compositestructure 1714. In some illustrative examples, composite structure 1714may have radius 1752. In these illustrative examples, second side 1748of composite filler 1702 may follow radius 1752.

First layer 1724 may form first side 1746 of composite filler 1702 whenfirst layer 1724 has first bent shape 1728. First layer 1724 may formsecond side 1748 of composite filler 1702 when first layer 1724 hasfirst bent shape 1728.

In some illustrative examples, composite filler 1702 may also includeextruded material 1754. Extruded material 1754 may be placed on the lastof plurality of layers 1718. Extruded material 1754 and plurality oflayers 1718 form third side 1756 of composite filler 1702. Third side1756 may contact composite skin 1716.

Plurality of layers 1718 may be formed of composite material 1706.Composite material 1706 may take the form of tape 1755, strips 1757, orother desirable composite material. Composite material 1706 may be cutto plurality of widths 1722 using cutting machine 1708.

Composite filler 1702 may be formed from composite material 1706 usingshaping equipment 1704. Shaping equipment 1704 may include base 1758 andplurality of dies 1760. First die punch 1000, second die punch 1100,third die punch 1200, fourth die punch 1300, fifth die punch 1400, andsixth die punch 1500 from FIGS. 10-15 may be physical embodiments ofplurality of dies 1760. Plurality of dies 1760 has plurality ofcross-sections 1762. Each of plurality of dies 1760 may be used to forma separate layer of plurality of layers 1718. Each of plurality ofcross-sections 1762 may form respective bent shapes 1720 of plurality oflayers 1718.

In some illustrative examples, shaping equipment 1704 may includeplurality of rollers 1764 instead of plurality of dies 1760. In theseillustrative examples, plurality of rollers 1764 may form respectivebent shapes 1720 of plurality of layers 1718.

Composite filler 1702 may have increased pull-off strength whenplurality of layers 1718 follows a radius of a composite structure. Byfollowing the radius of the composite structure, the composite fillermay direct loads along the radius.

The illustration of manufacturing environment 1700 in FIG. 17 is notmeant to imply physical or architectural limitations to the manner inwhich an illustrative embodiment may be implemented. Other components inaddition to or in place of the ones illustrated may be used. Somecomponents may be unnecessary. Also, the blocks are presented toillustrate some functional components. One or more of these blocks maybe combined, divided, or combined and divided into different blocks whenimplemented in an illustrative embodiment.

For example, manufacturing environment 1700 may not include compositestructure 1714. In this example, composite structure 1712 and compositeskin 1716 may form gap 1710.

Illustrative embodiments of the disclosure may be described in thecontext of aircraft manufacturing and service method 1800 as shown inFIG. 18 and aircraft 1900 as shown in FIG. 19. Turning first to FIG. 18,an illustration of a block diagram of an aircraft manufacturing andservice method is depicted in accordance with an illustrativeembodiment. During pre-production, aircraft manufacturing and servicemethod 1800 may include specification and design 1802 of aircraft 1900in FIG. 19 and material procurement 1804.

During production, component and subassembly manufacturing 1806 andsystem integration 1808 of aircraft 1900 in FIG. 19 takes place.Thereafter, aircraft 1900 in FIG. 19 may go through certification anddelivery 1810 in order to be placed in service 1812. While in service1812 by a customer, aircraft 1900 in FIG. 19 is scheduled for routinemaintenance and service 1814, which may include modification,reconfiguration, refurbishment, and other maintenance or service.

Each of the processes of aircraft manufacturing and service method 1800may be performed or carried out by a system integrator, a third party,and/or an operator. In these examples, the operator may be a customer.For the purposes of this description, a system integrator may include,without limitation, any number of aircraft manufacturers andmajor-system subcontractors; a third party may include, withoutlimitation, any number of vendors, subcontractors, and suppliers; and anoperator may be an airline, a leasing company, a military entity, aservice organization, and so on.

With reference now to FIG. 19, an illustration of a block diagram of anaircraft is depicted in which an illustrative embodiment may beimplemented. In this example, aircraft 1900 is produced by aircraftmanufacturing and service method 1800 in FIG. 18 and may includeairframe 1902 with plurality of systems 1904 and interior 1906. Examplesof systems 1904 include one or more of propulsion system 1908,electrical system 1910, hydraulic system 1912, and environmental system1919. Any number of other systems may be included. Although an aerospaceexample is shown, different illustrative embodiments may be applied toother industries, such as the automotive industry.

Apparatuses and methods embodied herein may be employed during at leastone of the stages of aircraft manufacturing and service method 1800 inFIG. 18. One or more illustrative embodiments may be used duringcomponent and subassembly manufacturing 1806. For example, compositefiller 1702 in FIG. 17 may be used during component and subassemblymanufacturing 1806. Further, composite filler 1702 may also be used toperform replacements during maintenance and service 1814.

The present disclosure provides a method for forming a composite filler.Layers of composite material are laid down on a forming tool. Arespective bend is formed in each of the layers to form the compositefiller comprising bent layers on the forming tool. The composite fillercomprising the bent layers is placed into a gap formed by at least onecomposite structure.

The composite filler may have increased pull-off strength as compared tocurrently used composite fillers. In some examples, the plurality oflayers may follow a radius of a composite structure. By following theradius of the composite structure, the composite filler may direct loadsalong the radius.

A first layer of the composite filler may form a first side and a secondside of the composite filler. The first layer may contact at least onecomposite structure. The plurality of layers may form a third side. Thethird side may contact a composite skin.

The description of the different illustrative embodiments has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different illustrativeembodiments may provide different features as compared to otherillustrative embodiments. The embodiment or embodiments selected arechosen and described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

What is claimed is:
 1. A method comprising: laying down a first layer ofcomposite material on a forming tool; forming a bend in the first layerby pressing the first layer against the forming tool using a first diepunch; repeating said laying down and forming steps for additionalsuccessive layers of the composite material using successively smallerdie punches to form a composite filler comprising bent composite layerson the forming tool, a respective bend in each of the successive layersbeing formed by pressing with a respective one of the smaller punches;and transferring the composite filler from the forming tool into a gapformed by at least one composite structure.
 2. The method of claim 1,wherein each of the successive punches has a different cross-section anda different angle forming the respective bend in a respective one of thesuccessive layers.
 3. The method of claim 1, wherein at least one of thesuccessive layers comprises multiple plies of the composite material. 4.The method of claim 1 further comprising: adding an extruded compositematerial into an open space formed by the bend of the final successivelayer prior to placing the composite filler into the gap.
 5. The methodof claim 1, wherein a cross-section of the composite filler issubstantially triangular.
 6. The method of claim 1, wherein eachsuccessive layer of composite material has a shorter width than a widthof a previous layer of the composite material.
 7. The method of claim 1,wherein the bend in each of the first and successive layers forms angledfirst and second layer sides parallel to first and second sides of thecomposite filler, respectively.
 8. The method of claim 1, wherein thecomposite filler comprises at least the first layer having a first bentshape, a first successive layer having a second bent shape, and a secondsuccessive layer having a third bent shape.
 9. The method of claim 1,wherein each of the successive die punches has a progressively smallerheight than a previous of the first and successive die punches.